BN from Great Falls to Havre(Pacific Jct) Montana

Can anyone give me insight into the time frame when this line was abandoned? I have a seen a number of BN maps that seldom included this connection. I recently found a BN map from 1974 that shows it as a complete thru line but all I have been able to find on the net was a Montana government document from the late 80’s asking to abandon a facility in Big Sandy. Is this about the time when that section was abandoned? Anyone know why? Lack of traffic etc…?

Thanks

Peter

(?)

Ft. Benton Sub still in service on BNSF/ Fort Benton to Great Falls (74.4-119.3), 74.4 to 73.58 used as tail track, never used (out in the weeds)

Big Sandy Sub still in Service on BNSF/ Pacific Junction to Big Sandy (0.0-32.1)

Big Sandy to Ft. Benton (32.10 to 73.58) abandoned 6/6/83 AB6_138F

Neither of the active lines is up for abandonment per STB (nothing on the SDM)

…from the track chart, the line is a low level branch line with mostly 90# and 110# jointed rail on old ties. (Old GN line, built in stages 1887-1902, Montana Division 3rd Sub)

The line was taken out of service between Big Sandy and Fort Benton due to unstable subgrade issues between Chappell (Loma) and Fort Benton. A similar situation plagued the now-abandoned Milwaukee line between Great Falls and Geraldine.

The Fort Benton to Great Falls segment is home to three shuttle grain train facilities: Kershaw, Tunis, and Carter.